The present invention relates to a gear shift device for tranmissions, and more particularly to a gear shift device which consists of a plurality of gear shift rods provided with connecting members and clutch-actuating shift forks and arranged in parallel with one another in such a manner that each of the gear shift rods can be moved in the lengthwise direction thereof, and a gear shift shaft provided with fingers engageable with the connecting members. The gear shift shaft is disposed at right angles to the gear shift rods and is rotationally and axially movable around and along its axis.
In a conventional gear shift device of this kind, a gear shift shaft is moved in its axial direction to engage a finger with a connecting member of a desired gear shift rod. The shaft is then turned to move the gear shift rod in its lengthwise direction and actuate a clutch by a shift fork mounted on the rod. In order to reduce the distance of axial travelling and the amount of angular displacement of the gear shift shaft in such a conventional gear shift device, a plurality of gear shift rods are arranged at short distances apart from one another in parallel. Nevertheless, the distances between the gear shift shaft and gear shift rods, and the distances between the gear shift rods and clutches are comparatively long. Accordingly, the lengths of the fingers, connecting members, or shift forks increase. In order to transmit sufficient driving force to a required part in such an arrangement, it is necessary to suitably reinforce the fingers, connecting members, or shift forks, so that the weight of these parts necessarily increases to a comparatively high level.
There is also a known gear shift device (German Patent Publication No. 2506570), in which two connecting members are fixed to the spaced portions of a gear shift shaft which extends at right angles to the parallel-arranged rods and is capable of being moved along and around its axis. In this gear shift device, the second finger is used to set the claws of a synchronizing clutch engaged with each other easily. The way of arranging the gear shift rods in this gear shift device is not different from that in the previously-described prior art device of this kind.